Whats the right backspacing?????

[CWLONGSHOT]

OK, he is my question, I am looking for opinions here:

 

I have a chance to get a set of 33X10.5X15 BFG MT's. I would put them on the MJ. Now there is plenty of lift, but I am conserned because when I tried the 33's from the TJ they hit hard at the lower rear edge of the front wheel openings. BUT, those where 33X12.5's on 8" rims with 3.25" of BS.

I will trim if needed, BUT would like to get them to fit with out trimming. I did trim a bit, maybe an inch from the offending edge and replaced the flairs a short time back.

I have longer adj LCA's on already. The last allignment, the caster was just plus of mid scale. I like my lifted Jeeps to be about max caster. I mention caster, because, I would legnthen them about 1/2" if the new coils (Read on) provide the correct amount of lift for a good balance with the rear and appropriate ammount of pos caster.

 

I am also going to swap out my tired, second hand Rustys 3" coils. They have sagged BAD. I doubt I have even 2" of lift from them. So I will be getting a new set, I'm thinking of R.E. coils, 4.5"ers. As I am at about 5.5" lift in the back. The measurement from ground to edge of my flair is right at 39" while my front is just over 36". (Of coarse this measurement includes tar height but you get the idea of the "rake" I currently have.) So I would like another inch to inch and a half up front to get a more level posture. I have ACOS now, but they are about as high as I feel comfortable making them. Thats why I am considerign the new coils now. I may or may not leave the ACOS in, depends on what I see/get with the new coils. Even at its lowest setting, ACOS's provide 1.25" of lift. I know the RE coils run tall.

 

As for the rims to make this whole thing work...and my REAL question. I am thinking 4 to 4.5" of BS will do this nicely and keep the rubber out of the fenders. Anyone been here and know for sure what fits and whet don't???

 

I have a set of five, factory 5 spoke aluminimum 15X7 rims with 5.25" of BS AND a set of AR outlaw II's 15X7 with 3.75" of BS. The factory will be not enough at 5.25" of BS and the outlaw II's may be too much at 3.75"..... OR because they are 7" not 8", they will be perfect????

 

Thanks for the opinions!!!

 

CW